TOKYO — The trade mission that helped launch United Airlines’ nonstop Denver-Tokyo flight attained its short-term goal of creating a critical mass of people needed to make an impression in the monstrous city, but it has only begun the long-term work of maintaining enough momentum to sustain the flight.

“Everybody knows that when a new flight starts, everyone wants to fly it. So how do we keep that buzz going?” said Kim Day, manager of aviation at Denver International Airport.

Red-eyed and with no conversation left in them as they traveled to Narita International Airport on Friday afternoon following three breakneck-paced days, each faction of the returning delegation — representing energy, politics, business, education and the airline itself — essentially had the same takeaway, with a slightly different flavor: Advocacy for the flight must not stop.

“This flight is only successful if we are still talking about this three, six, nine months from now,” John Brackney, president and CEO of the South Metro Denver Chamber, said during the return flight. “This all was very nice, but the whole point is that we continue to rise as an economic powerhouse.”

As partners and friends peeled off at varied phases of the return trip — a separate group went to Seoul, South Korea, to continue building ties there — hugs and jokes were exchanged as if the group had survived a battle together.

“The week’s takeaway is all the connections we made; now we just need to build them,” Day said.

The flight’s success depends on each stakeholder continuing to do its part, and United already has several events planned this month to grow the route’s base.

“We are bringing a group of Japanese media and Japanese business customers to Denver in two weeks,” said Dan Lynch, managing director of corporate and government affairs for United. “So it is basically the mirror image of what we just did in Tokyo.”

United’s immediate U.S. strategy is to pull traffic from feeder or flow markets — such as St. Louis and Austin — and try to get them to use Denver as their gateway airport versus Chicago, Dallas or Houston.

“We always go through Dallas-Fort Worth, and it’s just crazy and inconsistent,” said Jan Riepen, CFO and senior vice president of finance for the Austin Chamber of Commerce. “It would be nice to go through a calmer airport.”

Riepen was one of several people from Austin on the trip, as United is targeting their flow traffic for this route and sponsored them to join the delegation.

In two weeks, the airline is flying the 787 down to the Texas city for an exclusive event with some of its corporate partners and companies it is targeting. The goal is to shore up support for the aircraft and route.

“The point to all of this is to build a cadence of attention over the next several months. We didn’t want it to be all at once,” Lynch said.

As for the city and region, local leaders are focusing on three things: garnering tourism interest among the Japanese, nurturing Japanese companies interested in opening up an office in the U.S., and getting the Colorado business community to think bigger.

“We know of several Japanese companies looking to open in the U.S., and Denver is already on those lists,” said Mayor Michael B. Hancock. “It’s going to be about cultivating those relationships.”

Richard Scharf of Visit Denver and Al White of the Colorado Tourism Office have a return trip planned for November, when their teams will work with travel writers and travel brokers.

As a representative of south metro Denver’s business community, Brackney passionately believes in the region’s ability to be a global city.

“To do that we have to rise to it and see ourselves that way,” Brackney said. “I mean, are we willing to rally around what we are creating? What we are actually trying to do is build a culture.”

Brackney said that the delegation is responsible for finding smaller Colorado-based companies who may not be aware of the group’s foundational work being done in Japan.

“We need to get better at knowing who those companies are and getting them the resources provided by this critical mass, because (Tokyo) is huge and no one will know or care if they succeed or fail,” Brackney said.

Ultimately, he said, it is business that will make or break the flight’s success.

“Political leaders aren’t flying around the world all the time. They have a constituency to represent. It is the businesses that will (make) this flight a success,” Brackney said. “It’s the seats in the front of the plane that pay for this flight.”

Kristen Leigh Painter was a former business reporter who focused on airlines and aerospace coverage. She joined The Post in September 2011 and departed for the Minneapolis Star-Tribune in August 2014. She graduated from the University of Colorado Boulder with a master's in journalism after earning a bachelor's in history from the University of Wisconsin La Crosse.

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